Synthesis Of Supported Metal Catalysts Through Mechanochemical Approach And Study On Their Catalytic Hydrogenation Performance

As one kind of important catalysts,supported metal catalysts have been used to catalyze various chemical reaction.To date,the preparation of supported metal catalysts is always conducted in solvent.It consumes a large amount of solvents,needs long preparation time and requires the soluble metal precursors,which makes the preparation process tedious and results in the elimination of waste solvents.Mechanochemical synthesis method is usually carried out in little or no solvents.It is a facile and green solid-state preparation strategy and has been widely used in the preparation of metal alloys,zeolite,metal-organic frameworks?MOFs?,porous organic polymers and porous metal oxides.Take the advantages of mechanochemical synthesis approach,herein,we prepared a series of supported metal catalysts and studied their catalytic performance.?1?In this work,ZnO supported Pd catalyst?Pd/ZnO?was preparation by the mechanochemical synthesis approach.The Pd/ZnO was characterized by XRD and TEM,and the results showed that the Pd nanoparticles were well dispersed on the ZnO with the average size of 4.5 nm.The catalytic performance of the Pd/ZnO was also evaluated,it showed good catalytic activity toward the olefin hydrogenation reaction.Compared to the solution-based approach,the developed method is easily operated,consumes few time and does not need any solvents,it is a facile and sustainable approach.?2?MOFs have been regarded as good supports for the metal catalysts in recent years,due to the intrinsic porosity and functionality of MOFs.Massive efforts are devoted to prepare the MOFs supported metal catalysts,especially for these with encapsulation structures?MNPs@MOFs?.However,the poor stability of MOFs and homogeneous growth of MOFs in solution make these synthetic strategies complex and tedious,greatly hampering their practical application.Herein,Pd@ZIF-8nanocatalyst was prepared through the in-situ transformation of above synthesized Pd/ZnO with the assistance of ball milling.The structure of the as-prepared Pd@ZIF-8 was characterized by the XRD,TEM and N₂-sorption,and the results revealed that the Pd nanoparticles were well encapsulated in the ZIF-8 matrix.This approach was operated in solid state,which well avoiding the damage and homogeneous growth of ZIF-8.The catalytic performance of Pd@ZIF-8 was also evaluated,it exhibited high activity and selectivity to the hydrogenation of olefins.Furthermore,the versatility of this approach was also examined,this approach can be used to prepare many other MNPs@MOFs nanocatalysts,showing good versatility.